U.S. patent application number 09/883885 was filed with the patent office on 2002-01-31 for speaker enclosure venturi expander.
Invention is credited to Taylor, Ronald K..
Application Number | 20020011379 09/883885 |
Document ID | / |
Family ID | 26907734 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020011379 |
Kind Code |
A1 |
Taylor, Ronald K. |
January 31, 2002 |
Speaker enclosure venturi expander
Abstract
A venturi expander is mounted on a speaker enclosure to receive
the rearward-propagated sound waves and to extend the propagation
path. The venturi expander's reflective sides direct the rearward
sound to the sides or top or bottom of the speaker enclosure to
produce a reflected sound surrounding the speaker enclosure and
producing sound to the sides of the speaker substantially as
projected from the front of the speaker.
Inventors: |
Taylor, Ronald K.; (Miami,
FL) |
Correspondence
Address: |
RONALD K. TAYLOR
4465 SW 13TH TERRACE
MIAMI
FL
33134
US
|
Family ID: |
26907734 |
Appl. No.: |
09/883885 |
Filed: |
June 18, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60213057 |
Jun 21, 2000 |
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Current U.S.
Class: |
181/155 ;
181/148; 181/156 |
Current CPC
Class: |
H04R 1/345 20130101 |
Class at
Publication: |
181/155 ;
181/156; 181/148 |
International
Class: |
H05K 005/00 |
Claims
What I claim as my invention is as follows:
1. A speaker enclosure venturi expander, comprising, a speaker
enclosure having a front wall, rear wall, and a side wall,
respectively; a speaker having a speaker front and a speaker rear;
said speaker mounted in said front wall of said speaker enclosure
with said speaker front opening to ambient and said speaker rear
inside said enclosure; at least one bell port, with a bell port
inlet opposed to said speaker rear, and with bell port opening to
ambient; and a plurality of sound reflecting surfaces in said bell
port placed with at least two of said sound reflecting surfaces
arranged relative to each other and to said bell port inlet, to
reflect sound in a plurality of oblique sound propagation paths
from said bell port inlet to said bell port opening.
2. The speaker enclosure venturi expander of claim 1, wherein said
plurality of sound reflecting surfaces in said bell port are placed
relative to each other to reflect sound in respective oblique sound
propagation paths, in opposed directions relative to each other
3. The speaker enclosure venturi expander of claim 2, wherein said
bell port, said bell port inlet and said bell port opening, include
a direct propagation path from said bell port inlet to said bell
port opening and wherein said plurality of respective oblique sound
propagation paths, in opposed directions relative to each other,
cross said direct propagation path.
4. The speaker enclosure venturi expander of claim 1, wherein said
bell port opening comprises at least one bell port opening
reflective surface and said at least one bell port opening
reflective surface is arranged relative to said side wall to
reflect sound in a side propagation path from said at least one
bell port opening to said side wall and from said side wall to
ambient.
5. The speaker enclosure venturi expander of claim 4, comprising at
least two side walls and two bell ports with respective bell port
openings to ambient; and wherein, each respective said bell port
opening comprises at least one bell port opening reflective surface
and each said at least one bell port opening reflective surface is
arranged relative to a respective side wall to reflect sound in a
side propagation path from said at least one bell port opening to
said respective side wall and from respective said side wall to
ambient.
6. The speaker enclosure venturi expander of claim 1, wherein said
rear wall comprises a sound port opening from said speaker
enclosure to said bell port and at least two of said bell port
sound reflecting surfaces are placed opposed to said rear wall to
reflect sound from said sound port to said rear wall or to receive
sound reflected from said rear wall.
7. The speaker enclosure venturi expander of claim 6, wherein at
least two of said sound reflecting surfaces are stepped relative to
each other to increase the length of at least one of said oblique
sound propagation paths for one respective stepped reflective
surface relative to the length of another of said oblique sound
propagation paths for another of said respective stepped reflective
surfaces.
8. The speaker enclosure of claim 7, wherein said bell port inlet,
said bell port opening and said sound reflecting surfaces, comprise
a direct propagation path from said bell port inlet to said bell
port opening and wherein said plurality of oblique sound
propagation paths, cross said direct propagation path.
9. The speaker enclosure of claim 1, comprising an air port tube
with an inlet of said air port tube, opposed to said speaker rear
and with an outlet of said air port tube proximate said rear wall
and with the longitudinal axis of said air port tube passing
through said speaker rear.
10. The speaker enclosure of claim 9, wherein said air port tube
inlet is placed within an area of higher pressure area relative to
ambient, and arranged with said inlet located to exhaust said high
pressure area.
11. The speaker enclosure of claim 1, wherein said inlet of said
air port tube includes an adjustable opening.
12. A speaker enclosure venturi expander, comprising, a speaker
enclosure having a front wall, rear wall, and a side wall,
respectively; and with said rear wall joined to said side wall; a
speaker having a speaker front and a speaker rear; said speaker
mounted in said front wall of said speaker enclosure with said
speaker front opening to ambient and said speaker rear inside said
enclosure; at least one bell port, with a bell port inlet opposed
to said speaker rear, and with bell port opening to ambient; a
plurality of sound reflecting surfaces in said bell port placed
with at least two of said sound reflecting surfaces arranged
relative to each other and to said bell port inlet, to reflect
sound in a plurality of oblique sound propagation paths from said
bell port inlet to said bell port opening; said rear wall including
a rear wall port opening between said speaker enclosure and said
bell port; and said plurality of reflecting surfaces include said
rear wall;
13. The speaker enclosure venturi expander of claim 12, wherein
said inlet port includes said rear wall port opening.
14. The speaker enclosure venturi expander claim 12, wherein said
bell port is proximate said rear wall joined to said side wall.
15. The speaker enclosure venturi expander of claim 14, wherein
said bell port opening comprises at least one bell port opening
reflective surface proximate said rear wall joined to said side
wall; and said at least one bell port opening reflective surface is
arranged relative to said side wall to reflect sound in a side
propagation path from said at least one bell port opening to said
side wall and from said side wall to ambient.
16. The speaker enclosure venturi expander of claim 14, comprising
at least two side walls and two bell ports opposed to said speaker
rear with respective bell port openings to ambient; and wherein,
each respective said bell port opening comprises at least one bell
port opening reflective surface and said at least one bell port
opening reflective surface is arranged relative to a respective
side wall to reflect sound in a side propagation path from said at
least one bell port opening to said respective side wall and from
respective said side wall to ambient.
17. The speaker enclosure venturi expander of claim 14, wherein at
least two of said sound reflecting surfaces are stepped relative to
each other to increase the length of at least one of said oblique
sound propagation paths for one respective stepped reflective
surface relative to the length of another of said oblique sound
propagation paths.
18. The speaker enclosure of claim 18, wherein said bell port
inlet, said sound reflecting surfaces and said bell port opening
include a direct sound propagation path from said bell port inlet
to said bell port opening and wherein said plurality of oblique
sound propagation paths, cross said direct propagation path.
19. The speaker enclosure of claim 12, comprising an air port tube
with an inlet of said air port tube, opposed to said speaker rear
and with an outlet of said air port tube proximate said rear wall
and with the longitudinal axis of said air port tube passing
through said speaker rear, and wherein said air port tube inlet is
placed within an area of high pressure relative to ambient, and
with said inlet located to exhaust said high pressure area.
20. The speaker enclosure of claim 15, wherein said speaker
enclosure comprises a top wall or bottom wall and said wherein said
at least one bell port opening reflective surface is arranged
relative to said top wall or said bottom wall to reflect sound in a
side propagation path from said at least one bell port opening to
said top wall or said bottom wall, to ambient.
21. The speaker enclosure venturi expander of claim 13, wherein
said plurality of reflective surfaces comprises at least one
continuous reflective surface.
22. A speaker enclosure comprising, a front wall means, a side wall
means and a rear wall means; a speaker means for propagating sound
in a forward propagation path from said front wall means and in a
rear propagation path into said speaker enclosure; a bell port
means, including bell port opening means and bell port receiving
means for receiving said sound from said speaker means in said rear
propagation path and for directing said sound in a plurality of
oblique sound propagation paths in opposed directions relative to
each other, to said bell port opening means.
23. The speaker enclosure of claim 22, wherein said bell port
means, said bell port inlet means and said bell port opening means
comprises a direct sound propagation path means from said bell port
inlet means to said bell port opening means and wherein said means
for directing said sound in a plurality of oblique sound
propagation paths in opposed directions relative to each other
comprises means for directing said sound in a sound propagation
path crossing said direct sound propagation path and said bell port
means includes said rear wall means.
24. The speaker enclosure of claim 23, wherein bell port opening
means includes means for directing sound to ambient from said side
wall means and obliquely to said forward propagation path.
25. The speaker enclosure of claim 22, wherein said bell port means
comprises reflective means in a stepped relationship for increasing
a length of at least one of said oblique sound propagation paths
relative to another of said oblique sound propagation paths.
26. The speaker enclosure of claim 22, wherein said reflective
means comprises continuous reflecting means for increasing said a
length of at least one of said oblique sound propagation paths
relative to another of said oblique sound propagation paths.
27. The speaker enclosure of claim 22, including top wall means or
bottom wall means and wherein bell port opening means includes
means for directing sound to ambient from said top wall means or
said bottom wall means, obliquely to said forward propagation
path.
28. The speaker enclosure of claim 22, comprising air tube vent
means for exhausting a high pressure are relative to ambient, and,
wherein said air tube vent means includes an inlet means and means
for varying said inlet means and means for establishing a sound
propagation path from said speaker enclosure to said ambient.
29. The speaker enclosure of claim 22, wherein said side wall means
includes side wall reflecting means for propagating sound in said
rear propagation path in a plurality of straight paths to said bell
port receiving means.
30. The speaker enclosure of claim 22, wherein said side wall means
said air tube vent means include means for propagating sound in
said rear propagation path in a plurality of straight paths to said
bell port receiving means.
Description
CROSS REFERRENCE TO RELATED APPLICATIONS
[0001] This application is related to provisional patent
application number 60/213,057, filed Jun. 21, 2000 and claims the
benefit of the filing date of that application.
FIELD OF THE INVENTION
[0002] This invention is in the field of speaker systems and in
particular to speaker enclosures intended for operation at the
lower or bass frequencies of the audio range.
BACKGROUND
[0003] Speaker enclosures have been used as long as sound was
reproduced by a conventional electro-mechanical speaker. Enclosures
were used as a structural support to hold the speaker in place and
to baffle or reduce the effect of noises or out of phase sound
waves, created by the operation of the speaker and which interfered
with the reproduction of the a true sound intended to be
reproduced. In connection with speakers used to produce bass_tones
at the low frequency end of the audible range, for example from 150
Hz and below the speaker enclosure had to be made large enough so
pressures produced with the creation of the sound frequency waves,
did not interfere with the extended movement of the speaker cone at
those lower frequencies.
[0004] As background, speaker enclosures were built with baffles to
extend the path for backwardly projected out of phase audio waves
emanating from the rear of the speaker, to prevent these waves from
interfering with the forward directed waves from the front of the
speaker, because of the production of undesirable elements for
example standing waves, air turbulence port noise, whistling, and
port chuffing. In the case of speaker enclosures at the lower
frequency ranges, the enclosure size had to be large enough to
accommodate the pressures created at these lower frequencies which
prevented the reduction in the size of the enclosure and prevented
the enclosure from being made small so that pressure could not be
properly vented without producing the before mentioned undesirable
sound effects.
[0005] Many attempts have been made to solve the problems created
by low frequency enclosures for the purpose of making a smaller
size enclosure which do not suffer sound degradation associated
with higher internal pressures or backwardly directed waves. For
example, U.S. Pat. Nos. 5,517,573 and 4,196,792 show ways of using
ports to vent the enclosure so low frequency sounds may be
reproduced and whistling diminished and so the size of the speaker
enclosure could be made smaller. However, these devices were
limited as the use of ports to release the speaker internal
pressures while effectively managing the standing wave problem from
the backwardly projected waves, prevented a reduction in the size
of the enclosure. In connection with the projected sound, a large
portion of the sound energy in the backwardly projected sound was
lost as the object was to reduce the effect of the speaker on the
air mass inside the speaker enclosure and the efficiency of the
speaker was reduced as the energy associated with the backwardly
projected sound wave were not effectively utilized to enhance the
sound produced by the speakers. While U.S. Pat. No. 4,231,445 made
an attempt to disperse the backwardly or rearwardly projected sound
waves, relative to the forward projected sound waves from the front
of the speaker, the rearward sound waves were not utilized to
project the sound around the speaker enclosure or to extend the
sound path relative to the length of the sound waves at the lower
frequency range to prevent or minimize degradation of the total
sound from the speaker.
SUMMARY OF THE INVENTION
[0006] The venturi expander invention disclosed herein in its
preferred embodiments and according to the principles of the
disclosed invention, overcomes the problems of the prior art
devices in removing or relieving the pressures in the speaker
enclosure which impede the movement of the speaker cone at low
frequencies, for example at 150 Hz. and below, without the
accompanying distortion of port noise such as whistling or port
chuffing. The venturi expander operates with improved venting;
reducing the internal pressure of the enclosure, and permits the
volume and size of the enclosure to be reduced. Speaker size
reduction using the venturi expander can be accomplished without
sacrificing an extended audio path to disperse the backwardly or
rearwardly projected out of phase sound waves so their reflections
do not create cancellation by the mixing of out of phase rearward
sound waves with the forward projected sound waves from the front
of the speaker.
[0007] The efficiency of the speaker enclosure is enhanced by the
venturi expander by providing a path for dispersing the backwardly
or rearward projected sound waves, in an extended path through
surfaces which direct the movement of the sound waves out of the
enclosure in a compound path transverse to and through bell ports
placed in the speaker enclosure, extending the path of the sound
waves by reflection in the transverse direction while the
propagation of the sound waves is through the bell ports. An air
port tube in line with the rear of the speaker and opposed to the
rear of the speaker is vented at the rear wall of the enclosure,
providing a tube like path for relieving the pressure built up in
the enclosure around the speaker. The sound waves propagating in a
compound path out of the bell ports are in a pattern that causes
reflection of the sound waves from the sides, top and bottom of the
speaker enclosure and residual sound waves via air port tube
exhaust. These sound waves contribute to a 360-degree pattern when
combined with the sound waves projecting from the front of the
speaker.
[0008] The compound sound propagation path is through the speaker
enclosure rear wall port opening and the inlet to the bell ports
and through the bell ports to the bell port opening, and projecting
the rearward sound waves at an angle to the forward sound waves
projected from the front of the speaker. The effect is that of a
surround sound or 360 degree sound, so for example, in a live
performance musicians playing at the sides or rear of an instrument
amplified by a venturi expander design speaker enclosure may hear
the sound waves from that instrument as do those musicians sitting
in the path of the forward projected sound waves.
[0009] The bell ports, according to the principles of the venturi
expander and as shown in a preferred embodiment of the invention,
receive the sound waves emitted from the rear of the speaker and
reflected from the interior side walls of the speaker enclosure and
exterior of air port tube, and are arranged to reflect the sound
back and forth against the rear exterior wall of the speaker
enclosure and the sides of the bell ports. In a preferred
embodiment, the sides of the bell port are stepped with the
distance between the sides of the bell port and the rear wall of
the speaker increasing in the direction of propagation from the
bell port inlet to the bell port opening. In this way the reflected
waves will move obliquely with a direction component transverse to
the direct propagation path through the bell port, extending the
propagation path and reducing the effect out of phase sound waves
would have on the forward propagated waves from the front of the
speaker. At the same time, the energy in the rearward-propagated
sound waves is not lost or reduced to produce the effect of
360-degree sound wave dispersion.
[0010] In accordance with the principles of the invention and the
preferred embodiments disclosed, the air port tube extending
through the rear wall of the enclosure and through the venturi
expander, is in line with, and opposed to the rear of the speaker
and vents the higher than ambient air pressure out from the
enclosure. The tube may be of a varying size and is placed opposed
to the rear of the speaker to effectively vent the internal
pressure created by the operation of the speaker. The small size of
the air port tube inlet port relative to the cross sectional area
of the speaker at the inlet port, allows the flow of air and the
release of pressure without interfering with the backwardly
projected sound waves reflected internally from the walls of the
speaker and the exterior radial wall of the air port tube and out
the bell ports. The air tube cross sectional area may be reduced
where the size of the speaker is made smaller and may be blocked
where the size of the speaker does no create pressure levels
impeding the movement of the speaker cone. In this way, the air
port tube may be adjusted to accommodate any size speakers.
[0011] BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows the interior of the speaker enclosure in a top
view down into the enclosure with the speaker top removed and with
the venturi expander attached to the rear wall of the speaker
enclosure.
[0013] FIG. la shows the interior of the speaker enclosure, as
shown in FIG. 1. and with circular stepped walls of the venturi
expander forming a continuous bell port, corresponding to the rear
view of FIG. 2a.
[0014] FIG. 2 Shows the venturi expander in a rear view with the
rear wall and the opening in the rear wall through which sound
waves may propagate from the rear of the speaker to the venturi
expander.
[0015] FIG. 2a shows the venturi expander in a rear view as shown
in FIG. 2, with circular stepped walls of the venturi expander
forming a continuous bell port, corresponding to the top view of
FIG. 1a.
[0016] FIG. 3 shows the venturi expander is schematic form to show
the propagation paths of sound from the rear of the speaker to the
bell ports and to ambient from the port bell openings.
[0017] FIG. 4 shows the venturi expander with a circular port bell
and with the wall of the circular bell port being made
continuous
DESCRIPTION OF THE INVENTION
[0018] The invention according to its disclosed inventive
principles, is now shown and described with reference to its
preferred embodiments and to the Figures where the same numerals
are used to identify the same or similar parts with the same or
similar functions.
[0019] FIG. 1 in a top view generally shows a preferred embodiment
as a speaker enclosure 10. The enclosure is shown in a top view
looking into the enclosure with the top cover removed. The speaker
enclosure 10 as seen in this top view, is made of front wall 23,
side walls 11 and 19 and rear wall 21. Projecting through the front
wall 23 is the front or forward propagation direction 14 of speaker
13. The venturi expander is shown generally by numeral 33 and is
mounted to the rear wall 21 by means of mounting pins 47 and 49.
Passing through rear wall 21 is an air port tube 35 extending into
the speaker enclosure 31, with an inlet port 39 opposed to the rear
of speaker 13, shown generally by numerals 12 and 25, and a flared
portion 41 terminating in outlet port 37. Surrounding the air port
tube 35 is a circular port opening through rear wall 21 shown by
numeral 22 and having a radial width shown by numerals 24.
[0020] As may be seen in FIG. 1, the venturi expander includes one
or more bell ports shown as bell ports 66 and 68, with respective
bell port openings to ambient 67 and 69, located to receive sound
from the rear 12, of speaker 13 propagated toward the venturi
expander, through circular port 22 opening in rear wall 21. An air
port tube 35 shown in a preferred embodiment as in line and opposed
to the rear 25 of the speaker 13, extends through rear wall 21 and
terminates in a flared section 41 opening 37 to ambient. The inlet
of the air port tube is proximate the rear 12 of speaker 13 to
place the inlet in an area of higher pressure relative to ambient.
The bell ports 66 and 68, as shown in a preferred embodiment, may
be formed of stepped sides as shown in FIG. 1 or in a continuous
side as shown in FIG. 4, arranged so the stepped side or the
continuous side, are increasingly displaced from the rear wall 21
in the direction of direct sound propagation from the rear of the
speaker 13 through the bell port inlet, formed in a preferred
embodiment as shown in FIG. 1, by the circular port opening 22, the
rear wall 21 and the reflective surface 57 and the bell port
comprising the bell port reflective surfaces 57, 59, 61, 63 and 65
and the bell port openings 67 and 69, creating or defining a
passage of increasing width in the direction of the bell port
openings 67 and 69. Bell port walls are shown by numerals 59 and 61
in stepped relation with each other and with bell wall 57 and
forming bell port 66 with bell port opening 67, and by bell port
walls 63 and 65 in stepped relation with each other and with bell
wall 57 and forming bell port 68 with bell port opening 69. As
shown in FIG. 4, a continuous bell port wall 57 may be used instead
of the stepped walls as described. As would be understood by those
skilled in the art, the bell port walls as shown by numerals 59,
61, 63, and 65, may extend beyond the side walls 11 and 19 and the
top 16 and bottom 18, of speaker enclosure 10, as shown in FIG. 2
and 2a, or be coextensive with, or less than the dimensions of
these speaker wall 11, and 19 or top 16 or bottom 18. The bell port
walls 59, 61, 57, 63, and 65, may be arranged relative to each
other in a coaxial fashion as shown in FIGS. 1a and 2a, or be one
continuous wall as shown in FIG. 4, or may be varied in any other
suitable way, consistent with the principles of the disclosed
invention.
[0021] The circular port opening 22 is shown in phantom in rear
wall 21 with radial width 24 extending from the outer wall of the
air port tube 35 to the outer radial edge of the circular port 22.
As would be understood by those skilled in the art, the circular
port opening 22, in the propagation path of the sound waves from
rear 12 of speaker 13, to the venturi expander 33, may be varied in
shape and size and be made in one continuous opening or may be
discontinuous sections in the same radial distance from the axis of
the air port tube 35 or in a plurality of continuous openings
centrally or non centrally placed in the rear wall 21 of speaker
enclosure 10.
[0022] The seams where the stepped walls over lap are shown by
numerals 71, 73, 75 and 77. As shown in FIGS. 1a and 2a, where the
stepped walls are concentric or coaxial, the seams are shown as
circular.
[0023] The rear of the venturi expander is shown in FIG. 2. in
which the same numerals as in other Figures show the same or
similar parts, with rear wall 21 of the speaker shown in phantom.
Mounting pins 47, 47a and 49 and 49a are shown supporting the
venturi expander 33 on speaker enclosure rear wall 21. The outlet
port 37 of the air port tube 35 is shown with its flared portion
41. Surrounding the air port tube 35 is the circular port 22 in
rear wall 21 and extending radially from the air port tube 35 to
the outer edge 26 of the circular port 22, in the radial width
shown by numeral 24 in FIG. 1.
[0024] Referring to FIG. 1, the bell ports 66 and 68 are shown with
the stepped walls 57 and 63 and 65 for bell port 68 and it bell
port opening 69 to ambient and 59 and 61 for bell port 66 and its
bell port opening 67 to ambient and extending away from the rear
wall to define an increasing opening in the direction of direct
propagation of the sound from the interior 31 of the speaker
through the circular port 22 and to the stepped walls of the bell
ports 67 and 68. As would be apparent to one skill in the art, the
stepped walls may be circular, or coaxial or arranged in any other
suitable arrangement which achieves the effect of a widening sound
port in the direction of propagation. In a preferred embodiment,
the stepped walls overlap each other in circular seams as shown in
FIG. 2 and FIG. 2a, the venturi expander bell ports may extend
beyond side walls 11 and 19 and top 16 and 18, all shown in phantom
view.
[0025] A preferred embodiment as shown in FIG. 1a. and FIG. 2a,
shows a continuous circular bell port instead of the two separate
bell ports 67 and 69 as shown in FIG. 1. The outer most stepped
circular wall is shown by numeral 59, the intermediate stepped
circular wall is shown by numerals 61, and the overlapping seams by
numerals 77 and 75. A top view of the venturi expander as shown in
FIG. 1. is as shown in FIG. 1a with circular walls as shown in FIG.
2a. As would be known to those skilled in the art, the shape or
size of the reflecting walls and the shape and size of the opening
shown, may be varied without departing from the principles of
disclosed invention. In particular, the bell ports may be
constructed with reflecting surfaces separate from the surfaces of
the rear wall, without departing from the disclosed inventive
principles.
[0026] As would be understood by one skilled in the art, the bell
ports 66 and 68 as shown in FIG. 1 and FIG. 2 or the circulars bell
port as shown in FIG 1a, and 2a, may be varied by sectioning the
continuous bell port of FIG. 1a and 2a or making the outer stepped
wall extend beyond or coextensive with the top, bottom and sides of
the speaker enclosure side walls 11 and 19 and top and bottom 16
and 18, or of a smaller dimension or change the shape or location
of the circular port 22. In accordance with the principles of the
invention, the cross section of the air port tube 35, the distance
between the stepped walls of the bell ports 67, 69, and the size
and shape placement of the port 22 in rear wall 21, may be varied
from that shown in a preferred embodiment to derive the best
performance of the venturi expander consistent with the size of the
speaker and the speaker enclosure.
[0027] As seen in FIGS. 1 and 2, the outermost stepped wall of the
bell ports 66, 68, extend beyond the side walls 11 and 19 of the
speaker enclosure. Depending on the performance desired from the
venturi expander, the bell ports as formed by the stepped walls,
may be extended beyond the top 16 and bottom 18 of the speaker, as
explained above.
[0028] The operation of the venturi expander as shown in preferred
embodiments above or as may be varied by one skilled in the art is
explained with reference to FIG. 3, wherein the venturi expander is
shown in schematic form showing the sound propagation scheme of the
venturi expander. In the schematic of FIG. 3, the same numerals are
used to show the same or similar parts as in all other drawings.
The arrows shown without numerals represent the sound energy in the
form of acoustic sound waves produced by speaker 13 from its front
14 in the form of forward propagated sound waves and to the rear
from its back 12 in the form of rear propagated sound waves. Sound
waves propagated from the rear 12 of speaker 13, are in a path
toward the rear wall 21 along air port tube 35 and reflected from
the sides 11 and 19. The air port tube 35 placed in line and
opposed to speaker 13, provides an exhaust for the higher than
ambient air pressure produced by the movement of the cone of
speaker 13 and serves as an exhaust for that pressure as would be
well known to those skilled in the art. With the exhaust of the air
through air, port tube 35 is residual sound, which is passed to
ambient through air port tube outlet port 37.
[0029] The sound directed to the sides and along the sides of air
port tube 35, propagates out the circular port opening, as shown in
a preferred embodiment 22 and to the stepped reflecting surfaces
57, 63 and 65 and 57, 61 and 59 and out to ambient through
respective bell port openings 67 and 69. These reflecting surfaces
cause the sound waves to move in a reflective path in an oblique
path with a directional element transverse to the direct sound
propagation path from the bell port inlets through the bell ports
66, 68, to the bell port opening and out of out bell ports openings
69 and 67, As the sound waves propagate through the widening path
of the port bells shown in FIGS. 1, 1a, 3, and 4, the sound
propagation pattern of the sound waves is spread about the bell
port at its openings 67 and 68 into ambient causing the sound waves
to be directed out from the speaker, with a portion of the sound
energy being directed to, and reflected off the sides 11, 19, or in
the case where the venturi expander extends beyond the top 16 or
bottom 18, of the speaker enclosure, as shown in FIGS. 1a and 2a,
with a portion of the sound energy being directed to and reflected
off the top or the bottom of the speaker enclosure. In this way,
the sound from the speaker sides produces the effect of sound
radiating around the speaker with reference to the front to back
direction of the speaker enclosure from the front wall 23 to the
rear wall 21.
[0030] The propagation path of the sound waves from the rear 12 of
speaker 13 is extended or elongated by reflection within the
speaker enclosure 31, by the interior of the side walls 11 and 19
and the exterior of air port tube 35 and by reflection within the
bell ports 66 and 68 which alter the direct sound propagation path
and extend it by directing the sound waves obliquely to the direct
sound propagation path with a directional element transverse to the
direct sound propagation path by reflection between the reflective
surfaces of the bell ports, as shown in FIG. 3. As the sound waves
propagate, through the widening path of the port bells, 66 and 68,
the sound waves are caused to move more slowly, reducing the
potential for interference with the forward propagating sound waves
from the front 14 of speaker 13. The sound waves propagating out of
bell port outlets 67 and 69, are dispersed obliquely to, or
directly with, or sideways from, the front to back direction of the
speaker enclosure, or the direction of sound propagation in a
forward direction from the front of the speaker, and substantially
around the speaker enclosure, for example radiating substantially
about the axis of the air port tube 35 and radiating towards the
front of the speaker enclosure and to the rear of the speaker
enclosure as shown in FIG. 3, by propagation paths from the bell
ports 66, 68, or from the bell ports to and from the sides 11, 19,
or top 16 or bottom 18, of the speaker enclosure 10 and by the
residual sound from the air port vent tube 35. In this way, the
object of spreading the sound about the speaker enclosure radially
outward from the sides of the speaker enclosure is so musicians
sitting at the side of the amplified sound of another musician, can
hear the same music or sounds as those in front of the speaker
enclosure.
[0031] Various adjustments may be made to the shape of the port
bells, the air port tube, the size of the ports used in the
propagation path and the distances between the elements without
departing from the principles of the invention. For example, as
shown in FIG. 4, the circular port bell shown in FIG. 1a, and 2a,
may be a continuous wall instead of a stepped wall. As would be
known to those skilled in the art, the sound patterns may varied by
varying the configuration, size and spacing of the various parts of
the venturi expander, without departing from the principles of the
invention as shown and disclosed.
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